1. Field of the Invention
The present invention relates to an ink jet recording head to be formed by pressing a member that constitutes ink flow paths to be in contact with the head. The invention also relates to an ink jet cartridge and an ink jet recording apparatus provided with an ink jet recording head of the kind.
2. Related Background Art
Of the currently known various recording methods, an ink jet recording method is recognized as an extremely effective one, because this method is of a non-impact type that makes substantially no noises at the time of recording, while this method makes high-speed recording possible by use of an ordinary recording sheet without any particular fixing treatment given to the sheet.
FIG. 16 is a perspective view which schematically shows the general structure of the principal part of an ink jet recording head adoptable for the ink jet recording method described above. Also, FIG. 17 is a schematic view which shows the section taken along line 17xe2x80x9417 in FIG. 16.
In FIG. 16 and FIG. 17, a reference numeral 112 designates the elemental substrate (heater board) which is provided with a plurality of ink discharge pressure generating devices; 113, a grooved ceiling plate integrally formed with the grooves that become a plurality of ink discharge openings 101 and ink flow paths 105 conductively connected with the ink discharge openings 101, and also, with the recessed portions that become the wall portions 106 forming those of the ink flow paths, and a common liquid chamber 107 to supply ink to each of the ink flow paths 105; 111, a base plate (substrate) that forms each of the components thereon; 114, a spring member serving as means for mechanically pressing the ceiling plate 113 and the heater board 112 to be in contact with each other to constitute the ink flow paths 105 as described above.
The spring member 114 generates linear pressure by means of the folded end 114A, and presses the flat pressure portion 113B of the ceiling plate 113 arranged for the spring member so that the ceiling plate 113 and the heater board 112 are caused to be in contact. In this way, the spring member 114 is provided with the highly rigid folded end 114A whereby to press the flat upper surface 113B of the ceiling plate 113 in order to couple the two members, ceiling plate and substrate, by the application of pressure. This method has been in use conventionally.
However, an ink jet recording apparatus has been made increasingly smaller at lower costs in recent years. Along with such development, there is a need for making the structure of an ink jet recording head simpler. The structure, which is arranged to couple a ceiling plate with a substrate fixed to a base plate should be made simpler or smaller accordingly. Here, since the size of a head is determined by the size of the base plate, a structure may be arranged using a smaller-sized base plate or without using any base plate at all. Then, however, a problem arises that heat radiation, which is one of the functions to be provided by the base plate, becomes insufficient, and the temperature of the recording head having this structured is raised beyond a given temperature, hence causing the head to be damaged functionally, if ink in the ink flow paths should become short for some reasons.
Therefore, it is required to devise some means for controlling the temperature of the ink jet recording head structured as described above so as not to allow the temperature to rise more than a predetermined temperature.
The present invention is designed with a view to solving such problems. It is an object of the invention to provide an ink jet recording head capable of attaining high quality recording, while being structured without using any base plate or being structured to be smaller, but the temperature of such ink jet recording head is not caused to rise more than a predetermined temperature, while the substrate and ceiling plate thereof are in close contact. Further, it is an object of the invention to provide an ink jet recording apparatus having such ink jet recording head mounted on it for recording.
Here, it is required for a pressure member to obtain a high contactness between the ink flow path grooves of a ceiling plate and a substrate as its fundamental function. Therefore, it is another object of the invention to provide an ink jet recording head whose temperature is not caused to rise more than a predetermined temperature, while the substrate and ceiling plate are reliably in contact for the formation of such ink jet recording head.
In order to achieve each of the objectives described above, an ink jet recording head of the present invention comprises a grooved ceiling plate provided with a plurality of discharge openings for discharging ink, and a plurality of ink flow path grooves to form ink flow paths conductively connected with the discharge openings; a plurality of elemental substrates provided with a plurality of electrothermal transducing devices to generate thermal energy used for discharging the ink; and a metallic pressure member for pressing the plurality of elemental substrates to be in contact with the grooved ceiling plate, and the grooved ceiling plate and the elemental substrates being coupled to enable the ink flow path grooves and the electrothermal transducing devices to correspond to each other for the formation of ink flow paths, wherein the pressure member presses the reverse side of the surface of the elemental substrates having the electrothermal transducing devices provided therefor in order to couple the elemental substrates with the grooved ceiling plate.
Also, an ink jet recording head of the present invention comprises a grooved ceiling plate provided with a plurality of discharge openings for discharging ink, and a plurality of ink flow path grooves to form ink flow paths conductively connected with the discharge openings; a plurality of elemental substrates provided with a plurality of electrothermal transducing devices to generate thermal energy used for discharging the ink; and a metallic pressure member for pressing the plurality of elemental substrates to be in contact with the grooved ceiling plate, and the grooved ceiling plate and the elemental substrates being coupled to enable the ink flow path grooves and the electrothermal transducing devices to correspond to each other for the formation of ink flow paths, wherein on the reverse side of the elemental substrates having the electrothermal transducing devices provided therefor, a member having high thermal conductivity is arranged, and the pressure member presses the member having high thermal conductivity to couple the elemental substrates with the grooved ceiling plate.
In accordance with the present invention, heat generated by the elemental substrates is efficiently transferred to the pressure member for radiation even for an ink jet recording head having no base plate or having a smaller base plate than the conventional one, thus making it possible to prevent the temperature of the ink jet recording head from rising more than a predetermined temperature, while closely coupling the substrates and the ceiling plate reliable for the achievement of high quality recording.
Also, in accordance with the present invention, it is possible to perform ink discharges stable by closely coupling the substrates and the ceiling plate reliably.
Other objectives and advantages besides those discussed above will be apparent to those skilled in the art from the description of a preferred embodiment of the invention which follows. In the description, reference is made to accompanying drawings, which form a part hereof, and which illustrate an example of the invention. Such example, however, is not exhaustive of the various embodiments of the invention, and therefore reference is made to the claims which follow the description for determining the scope of the invention.